Comet Halley | Halley's Comet

This website simply lists information about Halley's Comet. The book, however, thoroughly investigates how ancient impacts and near misses changed religious beliefs around the world. The book is the result of years of research and countless interviews with astrophysicists, scientists and religious scholars. After reading it, you won't look at comets, meteor showers or religion in the same way.

About this Site

We've all heard of Halley's Comet, also known as Comet Halley or 1P/Halley, but what do we really know?

The mission of this site is to thoroughly explore a comet that once every 75 to 79 years has captured the imaginations of, and at times terrified, our ancestors. We'll compare long-forgotten historical observations of Comet Halley alongside modern discoveries courtesy of organizations like NASA and JPL. The site contains fascinating images, accounts and facts for Comet Halley including its size, orbital path, confirmed naked eye appearances dating back to 240 BCE, the biography of astronomer Edmond Halley, a detailed account of the U.S. Spacecraft that helped determine the comet's chemical composition and dimensions during a fly-by in 1986 and the passage of Earth through its "poisonous" tail in 1910, which sparked a run on gas masks and "comet pills".

Edmond Halley's name is forever associated with one of the greatest achievements in astronomy. Edmond predicted that a naked eye comet observed in 1531, 1607 and 1682 would become visible again in 1759. Sadly Edmond Halley passed away in 1742, and did not live to see the comet return on December 24, 1758. It became informally known as Halley's Comet and was later formally designated 1P/Halley. It was the first comet, in known history, to have its "P"eriodic orbit predicted.

Due to an occasional close brush with a planet or moon, the path of Comet Halley is unstable. It's orbital period has ranged between 75 and 79 years. This page takes a look at where Comet Halley comes from, its eccentricity and the path it travels through the constellations.

Calculations by modern-day astrophysicists have allowed observations of comets centuries or millennia ago to be definitively identified as previous apparitions of Halley's Comet. The earliest accepted sighting of Halley's Comet is 240 BCE.

If you don't see the information you're looking for in other categories, then try here. This page is full of information and facts for Halley's Comet's including its size, chemical composition, orbital period, speed and associated meteor showers.

Previous appearances of Halley's Comet have, at times, terrified the public. Its appearance in 1909 and 1910 was among them, after it was announced that Earth would pass through the comet's tail. To make matters worse, scientists announced that cyanogen had been found in the comet's tail. Although astronomers tried to convince the public that the poisonous cyanogen would not penetrate Earth atmosphere it didn't stop a run on gas masks and anti-cyanogen pills, or survivalists from preparing for the end of the world.

How big is Halley's Comet? The dimensions of Halley's Comet's nucleus are 10 x 5 x 5 mile (16 x 8 x 8 kilometer). It is shaped like a peanut. Due to the speed and size of Halley’s Comet, it would cause unimaginable disaster if it collided with Earth unleashing energy millions of times more powerful than the atomic bomb dropped on Nagasaki.